The invention relates to the timing of engines. More particularly to the timing of diesel engines by inserting a shaft into the flywheel timing hole to lock the flywheel in a predetermined orientation of the engine crankshaft so that the engine can be tuned. More particularly this allows the valves and injectors to be adjusted. This invention is especially useful for the tuning of Caterpillar engines.
U.S. Pat. No. 4,683,747 (Hall) discloses a timing pin assembly for a diesel engine. The apparatus includes a mounting plate, a housing assembly having a pressure and pilot guide side and a pin. When the flywheel timing hole is alined with the aperture in the mounting plate the pin maybe displaced into the timing hole by a pneumatic, electrical or mechanical means. This allows the user to set the pin without leaving the vehicle's engine compartment.
U.S. Pat. No. 4,895,016 (Cameron et al) discloses a timing assembly for a diesel engine which includes a threaded portion which is secured to the bell housing of the engine. Another name for bell housing used interchangeably in this field is flywheel housing. The device includes a threaded portion which is secured to the bell housing of a diesel engine. A spring biased piston extends through the bell housing and into a depression or detent in the fly wheel of the diesel engine. When the detent is aligned with the aperture in the bell housing through which the pin extends, the pin engages the detent to lock the flywheel, and accordingly the crankshaft and camshaft, in their predetermined locations. The locations are either at the 0 degree or 360 degree locations of the crankshaft. The timing of the valves and fuel injection is made in reference to both the 0 degree and 360 degree location.
The pin in the '016 patent is manually retracted by a finger secured to the pin. The finger extends outwardly from the housing of the pin for the manual retraction. The device may be secured to the bell housing and the pin will be spring biased against the flywheel. The engine is turned over until the depression or detent in the flywheel is aligned with the pin, and the bias of the compression spring against the pin moves the pin into the detent to lock the flywheel in the desired location.
U.S. Pat. No. 5,440,947 (Manganelli) discloses a timing assembly for a diesel engine which includes a threaded portion which is secured to the bell housing of the engine. A timing or locking pin is disposed within the cylinder and is movable longitudinally therein. Two springs oppose each other in biasing the timing or locking pin. A heavier spring extends between the outer end of the cylinder and a head on the pin, and a lesser spring extends between the head of the pin and the inner head of the cylinder. The heavier spring biases the timing pin into engagement with a detent in the flywheel, while the lighter spring retracts the pin from the detent. The cylinder has locking detents into which the sleeve pin may be moved to provide locking bias to move the timing pin inwardly into the recess or detent in the flywheel. When the sleeve pin is moved out of the detents, the force of the larger spring is relieved and the lighter spring moves the timing pin out of the detent to allow the flywheel to move.
Due to the general design engines, especially diesel engines, the space available in the engine compartment is limited. In many instances access to the location of the flywheel timing hole is limited by placement of other engine components. Due to these close quarters in which the timing pin apparatus is used, it is sometimes very difficult to insert and remove the timing lock pin device of the patents described before. The distance the timing assembly extends from the surface of the flywheel or bell housing many times makes it impossible to place the prior art on the housing. The devices are also difficult to repair should one of the springs break or the pin becomes bent. In many instances the pins used in the prior art will become bent if the engine is started while the pin in inserted into the detent of the fly wheel. In extreme cases the pin may be sheared off with the pin becoming lodged in the detent of the fly wheel. This results in the extensive maintenance to the engine. The maintenance of devices of the prior art is also a problem due to the dirt and grit that is present in all engine compartments. The problem with tight quarters, cost of the devices, repairs of the prior art and damage to the engine are overcome by the device of the present invention.